As I am an active geocacher, I am currently mapping forest trails (footways, bridleways) everywhere I go caching (mostly somewhere around my home). I think that is a useful improvement to the many roads that do already exist in OSM in this area.

I can't figure out why some mappers mark those way as "track", while it can easily be classified as "bridleway" or "footway" - not sure whether I should change that if I find clear hints on the official type of way ...

I think it depends on what the primary or biggest use is.
Is it wide enough for a 4x4 or could some vehicle drive down it? yes, then track.
No, Is it suitable for people to ride horses along? yes, then bridleway.
No, it might be too overgrown in places or have low branches crossing the path, it is a footway?

I do this similarly, though for me, if it's not a track, it's a footway by default, if it's not mainly used by or made for horses. This is in Germany, where I believe horses aren't generally allowed on such small paths.

Bridleway / public footpath / byway are legal definitions of rights of way and as such can only be marked after reference to the county Definitive Map which is a public document, (many rights of way are not signed on the ground and the routes ambiguous even with reference to a large scale map).
Most authorities have very good online documentation which supercedes even the Ordanance Survey who have a disclamer printed on every map to this effect : note that I do not believe that the use of this County reference material contravenes the OSM guidelines as it is not the track itself that you are tracing - just the information relating to its legal status.
In England and Wales, unless you are in a location which has access rights (another legal term) and you are on a footpath - track - service road etc that is not defined on the Definitive Map as a right of way then you are technically a tresspasser.
Legal status does not take into account the condition of a right of way or its suitability to use as a thoroughfare (there are may examples of fords across rivers which are considerably deeper than the average walker !).
We need to be very careful about our use of terms when mapping and it would be nice if the wiki could be unambiguous about this subject.
It may be that other countries have very different rules on rights of way and again this could prove an interesting wiki subject.

Yes, I think than LivingWithDragons and robx are right, as in Germany, people are allowed to use any path that is not marked as a private path as a fence. And normally, they are allowed to use this path in any way they like, if there are no signs prohibiting access for horses or bikes.

But I wouldn't mark a small path as a bridleway. Generally, I define this by the width of the path - if 3 persons can walk there next to each other in a comfortable way, it's a bridleway. If not, it's a footway.

@barrieu: There are not so many empty places of this size left in Germany, thus no fear of more airports to be mapped (there are plenty, anyway) ;-).

To be serious: It is true. In Germany you have, on a path, the right of way as long as it is not marked as private or within fenced private ground. This is true for being on foot, but not on any vehicle (including bikes!) and not on horses. Bikes are normally tolerated as long as they do not hinder footwalkers.

Stefan, I think you got my humor. I do also think that the rights of way are 'tolerated' to walkers and often cyclists in England, but I think that (in England), to mark a "track" as a right of way, when it clearly in law has no such status is no not doing the OSM any good service.
I think that the subject of rights of way is of great value to the OSM and as amature cartographers we should strive for accuracy in our work. Of course, there are many 'footpaths' that people use as means to get around but surely these should be marked differently to those enshrined in law as "rights" of way. I would often like to convert every gps track I generate into a track or footpath but if I did that then the whole of the area in which I live would be one great mass of tracks and totally meaningless as a means of navigation.
I am very interested in this subject and am just about to go on vaccation to an area (Scotland), which is as a whole country, effectively an access area, which means you can walk/ride/cycle just about wherever you wish. This may be a similar model to what you refer to in Germany.
I hope this thread of conversation continues and shall look forward to continuing the subject on my return.